I don't soak flats either. I used them alot when DD was little, they are all I used when in hossy. They are really bulky though, so I did like my bamboo prefolds for that reason, not as bulky.
I still have the prefolds, but don't use them as often & my flats are more for back up, spew catching & nappy free time.
Flats are great to have in weather like we are having at the moment though. They dry so fast!

WOSB - pink dot itti.